Electrical alternating current generator



Aug. 31; 1948.

H. TYZZER I ELECTRICAL ALTEh A'rING .GURR-ENT GENERATOR Filed June 28.1944 F I G- l HOWARD J. TYZZER INVENTOR ATTORNEY Patented Aug. 31, 1948ELECTRICAL ALTERNATING CURRENT GENERATOR Howard J. Tyzzer, Caldwell, N.J., assignor to Ferris Laboratories, BoontomN. J., a corporation of NewJersey Application June 28, 1944, Serial No. 542,497

11 Claims. 1

My present invention broadly relates to generating electricalalternating currents, and more particularly to generating the same in asystem making use of an electronic tube associated with electricalcircuits adapted to make the generation thereof possible under a varietyof circumstances.

'A particular object of my present invention is to make certain standardelectronic tubes and associated circuits more elastic in the matter ofthe range of frequencies throughout which electrical alternatingcurrents can be effectively generated with a minimum of circuitadjustments being needed toarrive at the particular results.

Practice of my present invention requires a type of electronic tube thatwill, when properly energized, materially amplify electrical alternatingcurrents, and a specific object in practicing the same isto effectivelymake allowances for the inevitable lack of uniformity of the inherentcharacteristics of standard electronic tubes of the same type arising inparticular out of mass production, and the differences in theconstructions of different types of amplifying electronic tubesparticularly with respect to the respective placements of the vitalinternal elements thereof with which my present invention canaccordingly be practiced.

In practicing my present invention, I deal in particular with thegeneration of electrical alternating currents of very high and ultrahigh frequencies as distinguished from the ordinary high frequenciescommon to radio operation practices until recently; and I have foundthat in certain regions therein, dependent somewhat upon the particulartype of amplifying electronic tube used, certain critical conditionsarise that require special treatments to remove them which are to bemore fully dealt with later, the manners in which the respectivetreatments are applied being of such natures as to be specific objectsof my present invention. In the cases of all of the standard amplifyingelectronic tubes accordingly suitable for participating in practicing mypresent invention, I have found that these critical conditions arisesomewhere in the frequency range above 100 megacycles.

In generating electrical alternating currents of low and comparativelyhigh with respect to low frequencies with amplifying electronic tubesand associated circuits, it has consistently been done by using one ofseveral methods of feeding some component of the alternatingmanifestations of the amplified energy from the output circuit into theinput circuit in such a manner that the active alternating energy of theinput circuitis built up to a point where the desired volume ofgenerated electrical alternating current is reached, the differentcircuit components and arrangements of them in the cases of the severalmethods having long been common knowledge. However, I have found withoutexception that in cases of the several methods each becomes less andless effective in the matter of causing generation as the frequenciesdesired increase after the frequency of megacycles is reached to soonthereafter become totally ineffective in that the generation involved isno longer had.

Considering this matter of thus ceasing to generate from a technologicaltheory point of view, the suggested thereby reason for it is that thebuilding up of the input energy required no longer takes place due totoo much departure from coincidence in the timing involved; so thatresorting to increasing the component of the alternating energy fed intothe input circuit at those frequencies above 100 megacycles involved inan effort to overcome said ceasing to generate at a point beyond whichit is desired to maintain progressive generation of electricalalternating currents of considerably higher frequencies apparently tendsto make the actions responsible for the ceasing to generate all the moreeffective, to overcome which the radical departures from prior practicesI have called into play are seemingly the only answers.

It is confidently anticipated that other objects of my present inventionperhaps of lesser importance than those given will be readily apparentto those competently acquainted with the particular art; so having giventhe principal objects of the same, it will now be described with the aidof the two figures of the accompanying drawings, in which figures, to asubstantial extent, like symbols have to do with substantially like inkind or in function elements.

Fig. 1 schematically displays my present invention in its more or lessgeneric form.

Fig. 2 schematically displays supplements to Fig. 1 whereby the range ofits application is materially extended.

Referring to Fig. 1, element T indicates an envelope of an electronictube having a source of electrons in the cathode K indicated as heatedby a filament F supplied with current by a batfi y B, a control grid CG,a screen grid SG made positive by being connected to battery B through avoltage reducing resistance R, an outer grid 0G maintained at cathodepotential by being connected thereto internally of envelope T and ananode A maintained at a positive potential by being connected to thepositive potential side of battery B. As is well known, the tubedescribed is inherently capable of materially amplifying electricalalternating currents or impulses because of the presence of control gridCG, and that when said tube is in action said grid will become andremain negative with respective to cathode K because of the presence 7of the grid-leak resistance R.

Element L indicates an inductance element, which may be either in rod orcoil form depending upon how small the inductance must be at the veryhigh and ultra high frequencies to be dealt with, and which, withvariable capacitance CT and fixed capacitance Cl", constitute theprincipal means by which the frequencies of the possible to generateelectrical alternating currents are determined. However, it must betakeninto consideration that all artificial and inherent inductances andcapacitances in any wise in a position to participate in the inductiveand. capacitance reactances of the principal means sum up therewith indetermining the frequencies of the possible to generate electricalalternating currents.

Element L indicates a coupling to inductance L in a position to extracta component of electrical alternating current therefrom, a substantiallymid-portion point of which is grounded as indicated by G" and isconsequently maintained at the potential of cathode K through ground G;from which it is perfectly clear that when the system is actively inoperation at anyone instant the respective potentials of the indicatedterminals a and b are opposite in polarity except at "those instantswhen the potentials of the positive and negative half cycles of theelectrical alternating currents become zero in shifting in polarity. Asindicated, through switch S a choice may be made in connecting eitherterminal a or -b to control grid CG through grid lead GI and capacitanceC. In addition to these connections, switch-Sprovides through terminalfor making the same connection of the termination of inductance L tocontrol grid CG.

As typical examples of what I have found as taking place in thematter'of frequencies at which generation of electrical alternatingcurrents is had when the three specified different connections are made;in the case of the connection from terminal a; in moving upward frombelow 100 megacyclcs an absolute shut down occurred at 110 megacycles;in the case of the connection from terminal I), in' moving downward from140 megacycles an absolute shut down occurred at 100' megacycles; and inthe case of the connection from terminal 0, in moving downward from 180megacycles, anabsolute shut down occurred at 140 megacycles.

In following upthe above outlined typical examples, on shortening gridlead GL as much as possible with it connected to terminal a it was foundthat the shut down occurred at 120 megacycles instead of 110 megacycles;andon shunting the resistance R with a capacitance C with the grid lead-GL connected toterminal c, in moving downwardpthatshut down occurred at100 megsaid shifting is not enough to make it unuseful to introduceregulation of the same by adjustment of the length of grid lead GL andvarying the capacitance of the indicated variable capacitance device Cwhen found to be respectively needed in the cases of working withdifferent types of amplifying electronic tubes. Because of capacitanceCbeing optionally supplementary, its presence indicates a preferred formof the arrangement of Fig. 1.

Referring to Fig. 2, it principally differs from Fig. 1 in displaying aplurality of selective means by which the frequencies of the possible togencrate; electricalialternating currents are determined Thisinclusionbecomes eminently important in cases of working in more than one band;of frequencies calling for shifting from one artificial, inductance toanother, in which cases it could happen that the frequency at which shutdown occurs would call for another artificial inductance of a-differentinductance value in order that'- operations at the different frequenciesinvolved' may becarried on. In such cases, if each artificial inductanceis built to have its own coupled thereto energy extraction, such as Iiin Fig. 1, means, it is gifted with the potentiality of facilitating thecalled for switchover.

In the elements symbolized by' Ll, CT and C2", Fig. 2'schematicallydisplays a duplication of theprincipal means by which the frequencies ofthe possible to generate electrical alternating currents are-determined,and further schematicall y displays in element Ll" that the artificialinductance Ll is equipped with its own coupled thereto-energy extractingmeans, but there is the difierence that the respective differentinductance-values of Land Ll go to make up a design making possibleworking in different bands of frequencies with reduced complications inmaking the change over.

As to means for expeditiously changing over from one band to another,means for maintaining the-anode A at its required' positive potentialare schematically" displayed: in its connection'to rotary element Phaving affixed theretoa conductivea-rm- D terminated by a conductiveindicated brushofany suitable material for making conductive contactwith either one of the are shaped conductors d and d which arerespectively displayed as connected to the positive side of battery Bthrough the'artificial inductances L and LI respectively. Rotatable withelement P, but not in conductive contact therewith, is a switch arm S-terminated in a preferably curved conductive plateE which, on beingrotated, predeterminedly takes up respective positions abreast ofpreferably curve like it conductive plates 11, b, c, a, b and c tothereby successively form with each of them a capacitance effectreplacing that of capacitance C of Fig. 1, and which is connected tocontrol grid CG' through grid lead GLand its connection to switch arm S.With this arrangement, theplates a', b and 0 respectively take theplaces of-contacts a, b and c in Fig. 1 while at the same timeeliminating the need for capacitance C of Fig; l, and the plates 11', band 0' take over forv their own band when the other bandisplaced out ofcommission byhaving arms Dand S join in with them in taking over; Sincedue to the very high frequencies involved the required capacitance inthe grid lead GL is very small, it is accordingly and yet helpfullynecessaryto use correspondingly small dimensions in designing thecapacitance introducing plates E, a and a, etc;

I have found that with a capacitance-device designed with sufiicientmass to efiectively and materially reduce the inherent ohmic resistancesand inductive reactances therewith with the latter rapidly increasingthe higher and higher the frequencies of the electrical alternatingcurrents with which used become, even in the cases of the high, veryhigh and ultra high frequencies with which I deal, a single device ofthe kind can be successfully'used as the variable devices CT and CTdisplayed in Fig. 2 with a substantial number of different in valueartificial inductances L, Li, etc., to cover an extremely wide range ofsuch frequencies in a number of bands; and that all of the change overoperations possible in the cases of Figs. 1 and 2 can be automaticallycarried out by operations arising out of rotatary movements of the usualshafting of variable capacitance devices. I include an indicated displayof these findings in Figs. 1 and 2 by linking the capacitancesschematically displayed to the controls schematically displayed bydotted lines. The points at which the automatic actions take place areeasily transferable to and indicatable on the usual variable capacitancedevice dial.

From a strict technological theorizing point of view, I am not certainas to What factors are involved in the way of relative actions that areresponsible for the phenomena behind the shiftable results I haveobtained; however, it seems that to a large extent they involve timefactors that are not at all susceptible to being rooted out and pinneddown. However, thanks to the tell tale instruments we now have, I havebeen able to quite accurately find at what points the opposing factorssufficiently sum up to force an absolute shut down, which, from apractical application point of view, is all that need be actually known.

I find it particularly desirable to electrostatically screen the controlgrids CG schematically shown by Figs. 1 and 2 from the respective anodesoi the tubes involved by the properly energized for the purpose screengrids SG also schematically shown by said figures, as it is clearlyobvious that unless such is done there will be in each case a secondelectrostatically reactive energy feedback path between the respectiveanodecathode and grid-cathode circuits shown, which, instead of offeringany co-operative advantage to the functioning of my system, clearly canwell serve in each case as a source of very diflicult to handlecomplications which can well be even too difficult to handle at all inconnection with stably generating electrical alternating currents havingthe very high and ultra high frequencies in which I am particularlyinterested. Furthermore, said electrostatic screening obviously tends tomake the alternating currents generated more perfectly sinusoidal inwave form than would otherwise be the case.

While I have described my present invention in certain confinedrespects, it is apparent that modifications may be made and that nolimitations are intended other than those imposed by the scope of theappended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. In a system for generating electrical alternating currents ofsinusoidal wave form in a region of ultra high frequencies somewhere inwhich the inherent nature of the system per se renders it without thepower to further generate: the combination of a standard electronic tubehaving an electron source in spaced relation to an efiective electronattracting positive potential anode and a negative otential control gridinterposed therebetween in normal spaced relations thereto; apositivepotential screen=grid interposed between said grid and saidanode;v a circuit having'paralleled inductance and variable capacitanceof such respective values as to have electrical natural periodscorresponding 'in'part at least to the ultra high frequencies at whichthe system proves to be devoid-of the power to generateinterposed-between said anode and said electron source; an energyextracting coupling associated with said circuit having effectivelyopposed in phase terminations; and a capacitance including lead from thesaid control grid to means for selectively making conductive contactwith either one of the said energy extracting coupling terminations;whereby making therewith the right termination connection serves toautomatically revive the power to generate at the ultra high frequenciesdesired.

2. The combination of claim 1, in which the length of the control gridlead determines in part the neighborhood of the frequency at which thepower to generate ceases.

3. The combination of claim 1, in which 8. capacitance interposedbetween the control grid and the electron source determines in part theneighborhood of the frequency at which the power to generate ceases.

4. The combination of claim 1, in which a combination of the length ofthe control grid lead and a capacitance interposed between the controlgrid and the electron source determines in part the neighborhood of thefrequency at which the power to generate ceases.

5. The combination of claim 1, in which cessation of the power togenerate in moving upwards in frequency is overcome by the control gridlead being terminated in the anode side of the paralleled inductance andvariablev capacitance circuit in lieu of being terminated in one of theterminations of the energy extracting coupling.

6. The combination of claim 1, in which the capacitance in the lead fromthe control grid comprises a conductive plate positioned abreast of aconductive plate acting as one of the terminations of the energyextracting coupling.

7. In a system for generating electrical alternating currents ofsinusoidal wave form in a region of ultra high frequencies somewhere inwhich the inherent nature of the system per se renders it without thepower to further generate: the combination of a standard electronic tubehaving an electron source in spaced relation to an effective electronattracting positive potential anode and a negative potential controlgrid interposed therebetween in normal spaced relations thereto; apositive potential screen grid interposed between said grid and anode; aplurality of circuits comprising paralleled inductance and variablecapacitance and means for conductively interposing any one of saidcircuits between said anode and said electron source; an energyextracting coupling associated with a newly chosen one of said circuitshaving effectively opposed in phase terminations; and a capacitanceincluding lead from said control grid to means for selectively makingcontact with either one of said terminations of said energy extractingcoupling of the newly chosen circuit; whereby generation of electricalalternating currents can be effectively continued at frequencies wellbeyond the neighborhood of the frequency at which the power to generateceased due to the replaced circuit no eration.

- fisr'Thetoombinationof; claim 7, in :whiclnal-l :of theenergy:extraction couplings.terminationsare sovapositioned uas toberseparatelyvand' predeterminedlyimconnected .to: 1.-the=aeontrol. gridlead :t hroughia :single sselective control-1 mechanism.

"'9lrfii'he combinationrofi claim :7,'in+which-all of .the;-energy;extracting couplings terminations; respectively terminaterinaconductiver-plates so posi- :=t ionecli.asnto= beivseparate'ly and-predeterminedly -'ca,pacit-ively: connected; tof the control; r d, leadthrough: a single selective]yaeontrollecl conductive plfilte.

.ts -;10. gT-he combination of claim T1, in .which cessa- 15 :tion ofthe power to-generate in ,mqvingzupwards :in frequency is overcome bythe control grid: lead :being terminated in the- -anode side of;themaralleled inductance and variable capacitance circuit in :lieu ofterminating; the samein one of the, terminations of "the energyextracting; coupling.

11. The combination of claim '7, inuwhichj the variable capacitance forthe plurality of-circuits consists of elements designed withlsufficientmass to materially reduce the inherent ohmic resistances and inductivereactancesofthe same at the ultrahigh at least vtrequencies involved.

* HOWARD J. TYZZER.

